She is a human-appearing entity, maternally related to the inter-dimensional 'Faltine' race of energy beings.

The daughter of 'Umar' and niece of 'Dormammu', Clea has been the ruler of the 'Dark Dimension'.

As 'Sorceress Supreme' of the Dark Dimension, Clea possesses knowledge of magical lore through extensive studies of sorcery under her teacher and lover, Doctor Strange, who also trained her in hand-to-hand combat.

She also possesses vast powers involving manipulation of the forces of magic for a variety of effects, including transmutation, forming and throwing magical bolts of concussive energy...

...conjuring objects and energies...

...teleporting, telekinesis, levitation, mesmerism, thought-casting, controlling others' minds, casting illusions, and the tapping of extra-dimensional energy by invoking entities or objects of power existing in dimensions tangential to Earth's through the recitation of spells.